The present invention generally concerns data communications networks having primary and backup facilities and is specifically directed to a remote test and control system for testing and reconfiguring the facilities from a central location without the need for manual supervision at the network remote data terminal stations.
The wide acceptance and current popularity of data processing is evidenced not only by the amount of data processing equipment currently in use, but also by the marked interest of public and specialized common carriers in providing data communications networks for meeting the burgeoning data traffic demands arising from the flow of data between distant locations. These traffic demands and their dramatically increasing growth patterns are due in no small part to the system design philosophy that it is often economically expeditious, even if not absolutely necessary, to process at one centralized location data from a number of geographically separated data terminals. For example, necessity might apply to the rapidly increasing point of sale transactions wherein credit and inventory controls are executed from a central memory bank for a number of commonly owned retail stores; economical expediency might apply to the time sharing of an off site single large computer by a number of remotely located facilities rather than providing an individual small computer on site at each one of those facilities.
In either case, the marriage of data communications with data processing is a fact of commercial life and represents sizeable capital investments by the business community. Because of these investments it is essential that data communications systems, comprising the networks which provide the communication links and the data terminal stations connected thereto for transmitting and receiving the data information, be utilized to the fullest extent possible so as to most efficiently employ capitalized investment. Consequently, it is imperative that the system operate with as great a reliability as practicable to assure the greatest degree of availability for data transmissions. Moreover, delays in the acquisition of requested data may materially and detrimentally impact or even prove critical to a business operation because of the need for and emphasis on the continuity and speedy real time retrieval of information, the airlines industry being one example thereof. This provides even greater impetus for maximizing data communications systems reliability.
In accordance with the foregoing, it is not uncommon to find duplication of components in data communications systems so that when one component fails because of some malfunction it can be replaced by another to quickly restore service while the component malfunction is diagnosed and corrected and the component is restored to service, thereby maintaining service continuity in the intervening period. For instance, a number of remote data terminal stations might be interconnected with a central processing station by two communication links, a link being defined herein as a half or full-duplex two-way transmission path including all of the associated equipment for passing signals between the remote and central stations over any medium whether it be wire or air. The link can be a dedicated one devoted to a particular customer or in the case of the telephone system a dial circuit associated with the normal telephone switched network which is accessed by conventional telephone dialing. One link would be a primary, normally used for data traffic with the other being a backup for emergency contingencies in the event that the primary link develops a malfunction. In that case upon learning of the malfunction, the backup link would be placed into service in lieu of the primary link until the malfunction was diagnosed and corrected and the primary link restored to service. When the data communications network is one designed for bandwidth limited voice communications the backup link is quite often normally used for voice communications so as to maximize the use of capitalized investment. In this arrangement, voice communications would be forced to yield to data communications whenever the link was required as a replacement for its primary.
Once a backup arrangement is decided upon for the data communications network, in order to maintain the same consistency of reliability throughout the system, it is usually desirable to also provide backup components within each of the data terminal stations themselves. When the communications network is designed for bandwidth limited voice communications, as is the telephone system, it is not uncommon to supplement the requisite modem at each station required for interfacing the data terminal with the network with a back up modem. Consequently, if the primary modem malfunctions, the other modem acts as a replacement so as not to disable the data terminal during the period needed to diagnose and correct the malfunction and restore the primary modem to service.
Although the use of backup facilities ameloriates the longer term detrimental effects of malfunctions in data communications network, there still remains the problem of first, determining that there is a system malfunction; second, locating the malfunctioning component so that it can be isolated from the rest of the system; and third, replacing it with its backup counterpart to restore service while the malfunction is diagnosed and corrected. Since the time that the system or any part of it is down because of a malfunction is economically wasteful, it is imperative that this three-step operation be performed as expeditiously as possible. Once the presence of a malfunction is recognized, usually through some difficulty encountered by a user or a preventive maintenance program, the malfunctioning component is normally located through the cooperation of two people, one at the central processing site and the other at the data terminal stations for applying and interpreting the results of various tests which are performed. Not only does this entail delays since personnel have to be dispatched to the remote stations (although personnel could be stationed on site on a permanent basis this is not usually a viable economical alternative in view of the many stations which may comprise a system), but also the specialized training and employment of numerous people since in many cases the terminal stations which comprise a data communications system may be spread over an expansive area. With the dramatic growth of the data communications field and the great sums of money devoted thereto this is a serious problem. Recognizing the problem, remote test systems have been developed for testing data communications systems from a central location thereby obviating the need for personnel at the data terminal stations. However, these systems are not comprehensive in that they do not provide the full battery of tests needed to quickly and accurately detect and isolate malfunctioning components nor thereafter to expeditiously restore service by remotely placing the required backup facilities into operation.
With the foregoing in mind, it is a primary object of the present invention to provide a new and improved remote test and control system for use with data communications networks for determining and locating system malfunctions from a central location.
It is a further object of the present invention to provide such a remote test and control system having capability for reconfiguring the communications network facilities from the central location as required by replacing identified malfunctioning components with their backup counterparts.
It is still a further object of the present invention to provide such a remote test and control system which is easily and inexpensively made compatible with all portions of data communications networks despite their various configurations and equipment.
These as well as other objects may be readily appreciated by referring to the Detailed Description of the Preferred Embodiment which follows hereinafter together with the appended drawings.